The invention relates to a cooling arrangement, especially for a liquid cooled internal combustion engine of the type having a liquid/air heat exchanger or radiator and an engine driven blower fan for drawing air through the heat exchanger in the direction toward the engine. The invention is more particularly related to such an arrangement which includes a flexible air guide ring for guiding the flow of air from the heat exchanger and around and through the blower fan.
A blower or fan for the radiator of a motor vehicle is known from German Published Application (DE-OS) No. 29 24 568 which has a fan ring supported by a spoked wheel and surrounded by an air flow ring resulting in an air gap therebetween. A hollow axle fixedly attached to the internal combustion engine is provided for supporting a drive wheel, the blower wheel and the spoked wheel. The radiator and the air flow ring are connected to each other by means of bellows forming an air pocket. This arrangement exhibits disadvantages in that the weight of the fan ring and the spoked wheel upon hollow axles supporting the drive wheel and fan wheel influences the functioning of same so that a satisfactory reliable operation cannot be achieved.
Furthermore, an internal combustion engine with a cooling system is known from U.S. Pat. No. 2,668,523 featuring an axial fan surrounded by an air duct ring. The air duct ring is fixedly attached by means of gibbets to the internal combustion engine and a wind pocket is attained through utilization of an elastic rubber bellows attached to the air guide ring and the radiator. However, this arrangement exhibits a disadvantage in that the air gap between the axial fan and the air guide ring cannot be maintained sufficiently small enough to prevent the axial fan from hitting against the air guide ring due to imbalance movements of the axial fan in radial directions and due to vibratory movements of the air guide ring transmitted during operation of the internal combustion engine.
It is an object of this invention to provide a cooling device arrangement which not only achieves the smallest possible air gap between the axial fan and the air guide ring, but for the most part eliminates the pressure upon the bearing of the axial fan caused by the weight of the fan rings and the spoked support wheel.
The above-mentioned problems with the prior art are solved by the present invention by providing that the air guide ring is supported by at least one rigid support bracket attached to the engine and by a spoked support wheel rotatably borne at the circumference of the hub of the fan axle.
In especially preferred embodiments of the invention, the spoked support wheel is connected to the fan axle hub by means of a vulcanized rubber connection of U-shaped cross section at the outer race of a roller bearing carried at the hub. Preferred embodiments also include a glued connection of the flexible air guide ring at the radiator and a circumferential tension ring connection of the air guide ring at the spoked support wheel. To reduce air flow resistance the spokes of the air guide ring are formed with a droplet shaped cross-section in especially preferred embodiments.
Further features of an especially preferred embodiment include the construction of the hub as a housing for a visco-coupling for the blower fan, a cover plate part of the hub housing at the side facing the heat exchanger including an extension which accommodates the inner race of the roller bearing for the spoked support wheel.
The cooling device arrangement in accordance with the present invention features the advantage that the weight of the air guide ring and the spoked support wheel is eased by the gibbet or support arm bracket fixedly attached to the internal cumbustion engine. The spoked support wheel supporting itself upon the roller bearing essentially centers or aligns the air guide ring with respect to the axial fan so that if the operation of the fan becomes eccentric, the eccentricity is transformed to the air guide ring by means of the spoked wheel. This feature first allows the construction of a cooling device which is provided with a rather small air gap between the axial fan and the air guide ring. Furthermore, central forces that occur in the axial direction may, for example, as they influence the spoked wheel during the acceleration process of a motor vehicle, be transferred to the bearing support.